Waiting for 8.4 – array aggregate and array unpacker

Finally, we got very important addons to PostgreSQL, which help with dealing with arrays.

It solves a lot of problems, which were usually solved with standard cookbook code, which was in faqs, blog posts and number of examples on irc.

First, there is a function to build array as aggregate.

It was committed by Peter Eisentraut yesterday, with this commit message:
array_agg aggregate function, as per SQL:2008, but without ORDER BY clause
Rearrange the documentation a bit now that array_agg and xmlagg have similar
semantics and issues.
best of Robert Haas, Jeff Davis, Peter Eisentraut

Implement the basic form of UNNEST, ie unnest(anyarray) returns setof
anyelement. This lacks the WITH ORDINALITY option, as well as the multiple
input arrays option added in the most recent SQL specs. But it's still a
pretty useful subset of the spec's functionality, and it is enough to
allow obsoleting contrib/intagg.